1. Field of the Invention
The present invention relates to scroll compressors that may compress fluid by utilizing stationary and movable scrolls and particularly, to scroll compressors that can efficiently seal a high-pressure chamber or space within the scroll compressors. Such scroll compressors may be utilized in air conditioning systems and more preferably in vehicle air conditioning systems.
2. Description of the Related Art
A known scroll compressor is disclosed in Japanese Laid-open Patent Publication No. H11-6487, which scroll compressor includes a stationary scroll and a movable scroll disposed within a compressor housing. A compression chamber is defined by a space between the stationary scroll and the movable scroll. When the movable scroll moves with respect to the stationary scroll, the volume within the compression chamber is reduced and thus, fluid drawn into the compression chamber is compressed and discharged from the discharge port. The discharge port is provided within the movable scroll at the location corresponding to the compression chamber in its minimum volume. Fluid compressed in the compression chamber is discharged opposite to the stationary scroll. Further, the movable scroll has a boss that extends opposite to the stationary scroll. The boss is coupled to a drive shaft member such that the drive shaft member causes the movable scroll to move along an orbital path.
In order to prevent the compressed fluid from leaking to a lower-pressure chamber or space within the compressor housing, a seal is provided between the base plate of the movable scroll and the compressor housing so as to surround the boss of the movable scroll. However, according to the known scroll compressor, a relatively large area must be sealed in order to prevent the compressed fluid from leaking to the lower-pressure space, because the seal surrounds the outer circumferential surface of the boss.
It is therefore an object of the invention to provide improved scroll compressors that can effectively prevent the compressed fluid from leaking to a low-pressure space within the compressor.
In the representative scroll compressor according to the present teachings, fluid is compressed by utilizing a stationary scroll and a movable scroll and is discharged from a discharge port defined within the movable scroll. As the result, compressed fluid is discharged opposite to the stationary scroll. The movable scroll revolves or orbits with respect to the stationary scroll by means of a crank shaft. The movable scroll includes a boss that protrudes to the opposite side of the stationary scroll. A bush is coupled to the outer surface of the crank shaft. A seal is disposed between the bush and the boss.
According to the present teachings, high-pressure fluid can be prevented from leaking to low pressure spaces by sealing a relatively small area between the bush and the boss. Moreover, because the seal is disposed in a radial direction between the bush and the boss, a tight seal can be realized. Preferably, the seal may elastically deform in the radial direction of the crank shaft. Thus, the impact of the bush contacting the crank shaft, due to the compression force at the initial stage of operating the scroll compressor, can be reduced or alleviated.
Other objects, features and advantage of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.